System for air-conditioning and hot-water supply

ABSTRACT

A system for air-conditioning and hot-water supply is configured to selectively perform a cooling operation and a heating operation. The system includes: an outdoor unit having a compressor and an outdoor heat exchanger; at least one or more indoor units each of which is connected to the outdoor unit and includes an indoor heat exchanger; a hot-water supply unit connected to the outdoor unit so as to be arranged in parallel to the at least one or more indoor units and including a refrigerant-water heat exchanger; and a controller configured to monitor an occurrence of a request for hot-water supply from the hot-water supply unit during the cooling operation performed at at least one of the indoor units, and then to start the heating operation. The controller is further configured to determine a time point to resume the cooling operation based on at least one of an outdoor temperature and a target temperature of at least one indoor unit in the heating operation.

TECHNICAL FIELD

The present invention relates to a system for air-conditioning andhot-water supply that is equipped with a heat pump.

BACKGROUND ART

EP 2 653 805 A1 proposes a system for air-conditioning and hot-watersupply which is equipped with a heat pump and is capable ofsimultaneously performing air conditioning operation and hot-watersupply operation. The system includes an outdoor unit having acompressor and an outdoor heat exchanger, at least one indoor unitconnected to the outdoor unit and including an indoor heat exchanger, atleast one hot-water supply unit connected to the outdoor unit so as tobe arranged in parallel to the indoor unit. The hot-water supply unitincludes a refrigerant-water heat exchanger.

The above system disclosed in EP 2 653 805 A1 performs a coolingoperation and a heating operation. During the cooling operation, thehot-water supply unit cools down water. During the heating operation,the hot-water supply unit heats up water. Accordingly, no new hot-wateris supplied during the cooling operation.

On the other hand, it is necessary to store enough amount of hot waterat a target temperature in a water tank so as to meet demands fordomestic use of hot water in a kitchen, bath room and the like. Newhot-water can be supplied, for example, during night time in that demandfor a cooling operation is in general less often than day time. Thehot-water supply unit can be configured to output a request forhot-water supply based on time and temperature of hot water stored in awater tank connected to the hot-water supply unit.

However, a request for hot-water supply can occur during a coolingoperation performed at at least one indoor unit. Then the coolingoperation will be immediately turned off such that a heating operationcan start upon the request for hot-water supply. This means that theindoor unit in the cooling operation changes its operation into theheating operation against the cooling operation set by a user.

CITATION LIST Patent Literature

[PTL 1] EP 2 653 805 A1

SUMMARY OF INVENTION Technical Problem

The object of the present invention is to solve the problem above, andis to provide a system for air-conditioning and hot-water supply whichmaintain users' comfort even when a hot-water supply operation isnecessary.

The object above is achieved by a system for air-conditioning andhot-water supply and configured to selectively perform a coolingoperation and heating operation described herein. Advantageous effectscan be achieved as described below.

Solution to Problem

A first aspect of the present invention provides a system forair-conditioning and hot-water supply and configured to selectivelyperform a cooling operation and a heating operation, comprising: anoutdoor unit having a compressor and an outdoor heat exchanger; at leastone or more indoor units each of which is connected to the outdoor unitand includes an indoor heat exchanger; a hot-water supply unit connectedto the outdoor unit so as to be arranged in parallel to the at least oneor more indoor units and including a refrigerant-water heat exchanger;and a controller configured to monitor an occurrence of a request forhot-water supply from the hot-water supply unit during the coolingoperation performed at at least one of the indoor units, and then tostart the heating operation; wherein the controller is furtherconfigured to determine a time point to resume said cooling operationbased on at least one of an outdoor temperature and a target temperatureof at least one indoor unit in said heating operation.

With the configuration above, the system can resume the coolingoperation at an appropriate time point based on the outside temperatureand/or a target temperature of any indoor unit. For example, the lowerthe target temperature of any indoor unit is, the shorter the timeperiod of said heating operation is. Another example is that the higherthe outdoor temperature is, the shorter the time period of said heatingoperation is. The duration period of said heating operation is limitedin this way, and therefore the user's comfort can be ensured.

According to a preferred embodiment of the system for air-conditioningand hot-water supply mentioned above, the controller is furtherconfigured to transmit to all of one or more indoor units in saidcooling operation a stop signal to stop a fan arranged at each indoorunit.

The background is as follows. When an expansion valve located on adownstream side of an indoor unit is completely closed during a heatingoperation, a certain amount of the refrigerant remains in the indoorunit. This may cause lack of amount of the refrigerant. Accordingly, allexpansion valves corresponding to all indoor units in the system arepreferably kept to be slightly open when the system switches itsoperation from cooling to heating. Even an expansion valve of an indoorunit which is turned off is also preferably kept to be slightly open.This means that, during the heating operation after the hot-waterrequest, a hot refrigerant may be supplied to an indoor unit which isturned on for the interrupted cooling operation. Warm wind may come outfrom such an indoor unit whose heat exchanger transfers heat from thehot refrigerant to air if a fan keeps working. Accordingly, the fan ofsuch an indoor unit is preferably forced to stop so as not to send outwarm wind. Thereby, users' comfort can be ensured at least at a certainlevel. In this case, a sensor installed within or on the housing of eachindoor unit may not be able to precisely detect a current roomtemperature due to the heat radiated from the heat exchanger. Such asensor sometimes detects the temperature of the heat exchanger arrangedin the indoor unit. The time point to resume said cooling operation maynot be able to be determined based on an output from such a sensor. Thesystem according to this preferred embodiment can solve this problem anddetermine the time point without using a current room temperature.

According to another preferred embodiment of any one of the systems forair-conditioning and hot-water supply mentioned above, the controller isfurther configured to continue said cooling operation until receipt of asignal from each of all indoor units in said cooling operation, and thento start said heating operation; and the signal indicating that acurrent room temperature has reached to a target temperature of acorresponding indoor unit.

With the above configuration, the heating operation starts only when acurrent room temperature of each area has reached to a targettemperature. Each area corresponds to an indoor unit which performs saidcooling operation. Thereby, user's comfort for the cooling operation canbe furthermore ensured.

Each of the indoor units in the cooling operation transmits the signalto the controller when a current room temperature has reached to atarget temperature in the corresponding area. The current roomtemperature can be detected by a sensor arranged in each area where eachof the indoor units is installed. Such a sensor constitutes a part ofthe indoor unit, but is not necessarily located inside the housing ofthe indoor unit. The sensor can be arranged inside, outside or on thehousing of the indoor unit. The sensor can be arranged inside of acontroller of the indoor unit with which a user operates the indoorunit. An infrared sensor can be installed on the front panel of thehousing of the indoor unit to detect the temperature of the floor in thecorresponding area as the current room temperature, for example. Anotherexample of the sensor is a sensor which is independently arrangedoutside of the housing of the corresponding indoor unit. Such a sensoris arranged within the corresponding area and is equipped withcommunication means to transmit the detected temperature to thecontroller.

According to another preferred embodiment of any one of the systems forair-conditioning and hot-water supply mentioned above, the controller isfurther configured to determine the time point to resume said coolingoperation based on the difference between the outdoor temperature andany one of target temperatures of one or more indoor units which were insaid cooling operation.

Any one of target temperatures is, for example, the lowest targettemperature among the target temperatures of one or more indoor unitswhich were turned on for said cooling operation at the time of theoccurrence of the hot-water request. The controller preferably resumessaid cooling operation when the biggest difference between the outdoortemperature and target temperatures goes beyond a predeterminedthreshold value.

When a target temperature is lowered by a user in any area, it is anindication that the user starts feeling uncomfortable. Therefore,watching current target temperatures and the differences between theoutside temperature and target temperatures enable to determine whensaid cooling operation should be resumed.

According to another preferred embodiment of any one of the systems forair-conditioning and hot-water supply mentioned above, at least one ofthe indoor units includes a sensor within or on its housing, the sensorbeing configured to detect a room temperature.

Such a sensor arranged within or on the housing of an indoor unit maynot be able to precisely detect a room temperature during said heatingoperation. Nevertheless, said cooling operation can be resumed at anappropriate time point since the resume timing does not depend on anycurrent room temperature.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows an example of a refrigerant circuit formed by a system forair conditioning and hot-water supply according to an embodiment of thepresent invention.

FIG. 2 shows a block diagram showing functions of an outdoor controllerin FIG. 1.

FIG. 3 shows a level table stored in the outdoor controller in FIG. 1.

FIG. 4A shows an example of a status table stored in the outdoorcontroller in FIG. 1.

FIG. 4B shows an example of a status table stored in the indoorcontroller in FIG. 1.

FIG. 5 is a block diagram showing functions of an indoor controller ofthe indoor unit in FIG. 1.

FIG. 6 shows an example of a time chart for switching from a coolingoperation to a heating operation triggered by a hot-water request.

FIG. 7A shows an example of the main process performed by the outdoorcontroller in FIG. 1.

FIG. 7B shows an example of the main process performed by the outdoorcontroller in FIG. 1.

FIG. 8 shows an example of the flow of increase process during the mainprocess in FIGS. 7A, 7B.

FIG. 9 shows an example of the main process performed by the indoorcontroller in FIG. 1.

FIG. 10 shows one of the examples of the locations where a temperaturesensor is arranged.

FIG. 11 shows another example of a refrigerant circuit formed by asystem for air conditioning and hot-water supply according to anotherembodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

A preferred embodiment of the present invention will be described withreference to the drawings.

FIG. 1 shows an example of a refrigerant circuit formed by a system 10for air conditioning and hot-water supply according to an embodiment ofthe present invention. It should be noted that the relationship betweenthe sizes of components shown in the appended drawings may differ fromthe relationship between actual sizes of the components.

<Configuration of the System 10>

The system 10 is installed in a building such as an apartment, a hotel,an office building as well as a house for individuals. The system 10 isconfigured to selectively perform a heating operation accompanied byhot-water supply and a cooling operation. The system 10 performs theheating and cooling operations by using heat pump mechanism whichcirculates a refrigerant in the refrigerant circuit.

The system 10 includes an outdoor unit 110, at least one or more indoorunits 120 a, 120 b, and a hot-water supply unit 130, which are connectedto each other. Each of the indoor units 120 a, 120 b and the hot-watersupply unit 130 are connected in parallel to the outdoor unit 110 whichserves as a heat source unit. Although two indoor units 120 a, 120 b areshown in FIG. 1, the number of indoor units is not particularly limited.Only one indoor unit 120 or a plurality of indoor units 120 a, 120 b, .. . may be arranged in the system 10 according to the same manner as theindoor unit 120 a, 120 b.

The outdoor unit 110, the indoor units 120 a, 120 b, and the hot-watersupply unit 130 are connected by a gas main pipe 101 and a liquid mainpipe 102. The gas main pipe 101 and the liquid main pipe 102 serve as arefrigerant pipe through which the refrigerant flows so as to circulatein the refrigerant circuit.

Further, a water pipe 103 is connected to the hot-water supply unit 130so as to receive fresh water from and supply warm/cold water to a watercircuit 104. The water circuit 104 is outside of the system 10. Thewater circuit 104 supplies fresh water to the hot-water supply unit 130,and guides the warm/cold water from the hot-water supply unit 130 toareas where the water is used. The hot-water supply unit 130 isconfigured to heat or cool the supplied water, and store the heated orcooled water in a water tank 133.

<Outdoor Unit 110>

The outdoor unit 110 performs the heating operation or the coolingoperation on the outdoor unit side to supply heating energy or coolingenergy to the indoor units 120 a, 120 b and the hot-water supply unit130. The outdoor unit 110 includes a compressor 111, a switching valve112, an outdoor heating exchanger 113, an accumulator 114, and anoutdoor fan 115.

During the heating operation, the outdoor unit 110 forms a refrigerantcircuit for heating (hereinafter the heating circuit) in which theoutdoor heating exchanger 113, the switching valve 112, the accumulator114, the compressor 111, and the switching valve 112 are sequentiallyconnected in this order from the liquid main pipe 102 side toward thegas main pipe 101.

During the cooling operation, the outdoor unit 110 forms a refrigerantcircuit for cooling (hereinafter the cooling circuit) in which theswitching valve 112, the accumulator 114, the compressor 111, theswitching valve 112, and the outdoor heating exchanger 113 aresequentially connected in this order from the gas main pipe 101 sidetoward the liquid main pipe 102.

The compressor 111 is configured to suck and compress the refrigerant toa high-temperature and high-pressure state. The compressor 111 is notlimited to a particular type of compressor. For example, the compressor111 may be a reciprocating compressor, a rotary compressor, a scrollcompressor, and a screw compressor. The compressor 111 is preferably ofa type whose rotation speed can be variably controlled by, for example,an inverter.

The switching valve 112 is configured to switch the flow of refrigerantin accordance with a requested operation, i.e. heating or coolingoperation. The switching valve 112 is configured to switch therefrigerant circuit between the heating circuit and the cooling circuit.

The outdoor heat exchanger 113 is configured to function as a condenserduring the cooling operation, and function as an evaporator during theheating operation. The outdoor heat exchanger 113 exchanges heat withthe air sent from the outdoor fan 115 so as to condense or evaporate therefrigerant flowing therein. The heat exchange amount of the outdoorheat exchanger 113 can be controlled by, for example, varying therotation speed of the outdoor fan 115.

The accumulator 114 is disposed on the suction side of the compressor111, and is configured to store excessive refrigerant. The accumulator114 may be any container for storing excessive refrigerant.

The outdoor fan 115 is disposed near the outdoor heat exchanger 113 soas to send wind toward the outdoor heat exchanger 113. Preferably, thewind level of the outdoor fan 115 is variable by, for example, changingthe rotation speed of the corresponding motor.

<Indoor Unit 120 a, 120 b>

Hereinafter, the common configuration and function among the indoorunits 120 a, 120 b are explained. Therefore, the explanation about oneindoor unit is applicable to another indoor unit, and vice versa.

The indoor unit 120 a has a function of receiving heating energy orcooling energy from the outdoor unit 110 so as to perform the heatingoperation or the cooling operation on each indoor unit side. The indoorunit 120 a includes an indoor heat exchanger 121 a and an expansionvalve 122 a, which are connected in series to each other. Further, anindoor fan 123 a is disposed near the indoor heat exchanger 121 so as tosend out warm or cool air from the indoor unit 120 a.

The indoor heat exchanger 121 is configured to function as a condenserduring the heating operation, and to function as an evaporator duringthe cooling operation. The indoor heat exchanger 121 transfers heat fromthe refrigerant flowing therein to the air supplied by the indoor fan123 a so as to condense or evaporate the refrigerant.

The expansion valve 122 is configured to reduce the pressure of therefrigerant and to expand the refrigerant. It is preferable that theopening degree of the expansion valve 122 is variably controllable.Examples of such valves include precise flow control means such as anelectronic expansion valve, and inexpensive refrigerant flow controlmeans such as a capillary tube.

The indoor fan 123 a is disposed near the indoor heat exchanger 121 soas to send out warm or cool wind from the indoor unit 120 a andintroduce air from outside into inside of a housing (not shown) of theindoor unit 120 a. Preferably, the wind level of the indoor fan 123 a isvariable by, for example, changing the rotation speed of thecorresponding motor.

<Hot-Water Supply Unit 130>

The hot-water supply unit 130 has a function of transferring heatingenergy or cooling energy from the outdoor unit 110 to water so as toperform the heating operation or the cooling operation thereon. Thehot-water supply unit 130 includes an indoor-water heat exchanger 131,an expansion valve 132, and a hot water tank 133. It is to be noted thatalthough only one hot-water supply unit 130 is shown in FIG. 1, thenumber of hot-water supply units is not particularly limited and two ormore hot-water supply units may be arranged within the system 10 inaccordance with the same manner as the hot-water supply unit 130.

The indoor-water heat exchanger 131 is arranged within the space definedby the water tank 133 such that the indoor-water heat exchanger 131transfers heat from the refrigerant flowing therein to the water storedin the water tank 133. The water heated or cooled by the indoor-waterheat exchanger 131 is supplied to the water circuit 104.

The expansion valve 132 in the hot-water supply unit 130 has the samefunction as the expansion valve 122 a in the indoor unit 120 a.

The water tank 133 stores water. Preferably, the water tank 133 storeshot water for domestic use in a kitchen, bathroom and the like. Thewater tank 133 thermally insulates the stored water therein fromoutside. The hot water in the water tank 133 is preferably kept at atarget temperature set by a user, which will be explained later.

Preferably, a sensor (not shown) is arranged to detect status data ofthe water stored in the water tank 133. The status data of the storedwater includes, for example, the temperature of the water and/or theamount of the water. The sensor can be arranged within the space of thewater tank 133, on the outer surface of the water tank 133, and/or theoutlet of the water tank 133.

As described above, in the system 10, the compressor 111, the switchingvalve 112, the indoor heating exchanger 121 a, the expansion valve 122a, and the outdoor heat exchanger 113 are connected in series to eachother. Likewise, the compressor 111, the switching valve 112, theindoor-water heat exchanger 131, the expansion valve 132, and theoutdoor heat exchanger 113 are connected in series to each other.Further, the indoor heat exchanger 121 a and the indoor-water heatexchanger 131 are connected in parallel with regard to the outdoor heatexchanger 113. Thus, the refrigeration circuit for circulatingrefrigerant is formed.

Although not illustrated in FIG. 1, the system 10 may further include asensor that detects a discharge pressure of the refrigerant, a sensorthat detects suction pressure of the refrigerant, a sensor that detectsat discharge temperature of the refrigerant, a sensor that detectssuction temperature of the refrigerant, sensors that detect temperaturesof the refrigerant flowing into and flowing out of the outdoor heatexchanger 113, a sensor that detects a temperature of outside air takeninto the outdoor unit 110, sensors that detect temperatures of therefrigerant flowing into and flowing out of the indoor heat exchanger121, and a sensor that detects a temperature of water stored in thehot-water tank 133. Measurement information obtained by these varioussensors is transmitted to a controller 100, 200, 300, which will beexplained later, and is used to control components in the system 10.

<Heating and Cooling Operations>

During the cooling operation, the outdoor unit 110 and at least one ofthe indoor unit 120 a perform the cooling operation. During the heatingoperation, the outdoor unit 110 and at least the hot-water supply unit130 perform the heating operation. The controller 100, 200, 300 of thesystem 10, which will be explained later, controls relevant componentsof the system 10 to perform the operations below.

<Heating Operation>

The system 10 is controlled during the heating operation to realize theperformance below. A low-pressure gas refrigerant is sucked into thecompressor 111. The refrigerant is compressed into ahigh-temperature-high-pressure status in the compressor 111, isdischarged therefrom, passes through the switching valve 112, and flowsout of the outdoor unit 110 through the gas main pipe 101. Then thehigh-pressure gas refrigerant that has flowed out of the outdoor unit110 flows into the indoor unit 120 and the hot-water supply unit 130.The refrigerant that has flowed into the indoor unit 120 flows into theindoor heat exchanger 121. The refrigerant that has flowed into thehot-water supply unit 130 flows into the indoor-water heat exchanger131. The high-pressure gas refrigerant is condensed in the indoor heatexchanger 121, turns into a high-pressure liquid refrigerant, and flowsout of the indoor heat exchanger 121. Likewise, the high-pressure gasrefrigerant turns into high-pressure liquid refrigerant in theindoor-water heat exchanger 131 and flows out thereof.

The high-pressure liquid refrigerant from the indoor heat exchanger 121is subjected to pressure reduction by the expansion valve 122, and turnsinto a low-pressure-2-phase gas liquid refrigerant which flows out ofthe indoor unit 120 through the liquid main pipe 102. Likewise, thehigh-pressure refrigerant from the indoor-water heat exchanger 131 turnsinto a low-pressure-2-phase gas liquid refrigerant or low-pressureliquid refrigerant which flows out of the hot-water supply unit 130through the liquid main pipe 102. Then the low-pressure refrigerantflows into the outdoor heat exchanger 113, exchanges heat with the airsupplied from the outdoor fan 115, turns into a low-pressure gasrefrigerant, and flows out of the outdoor heat exchanger 113. Therefrigerant that has flowed out of the outdoor heat exchanger 113 passesthrough the switching valve 112 and the accumulator 114, and is suckedinto the compressor 111 again.

<Cooling Operation>

The system 10 is controlled during the cooling operation to realize theperformance below. The low-pressure gas refrigerant is sucked into thecompressor 111. The refrigerant is compressed into ahigh-temperature-high-pressure status in the compressor 111, and isdischarged therefrom. The high-temperature-high-pressure refrigerantflows into the outdoor heat exchanger 113 via the switching valve 112.The high-pressure-gas-refrigerant that has flowed into the outdoor heatexchanger 113 exchanges heat with the air supplied from the outdoor fan115, and turns into a high-pressure liquid refrigerant. Thehigh-pressure liquid refrigerant flows out of the outdoor unit 110through the liquid main pipe 102, and then flows towards at least oneindoor unit 120 a. The refrigerant that has flowed towards the indoorunit 120 a is subjected to pressure reduction by the expansion valve 122a so as to turn into a low-pressure-2-phase gas liquid refrigerant or alow-pressure liquid refrigerant. The refrigerant then flows into theindoor heat exchanger 121.

The low-pressure refrigerant that has flowed into the indoor heatexchanger 121 is evaporated in the indoor heat exchanger 121 and turnsinto a low-pressure gas refrigerant, and flows out of the indoor heatexchanger 121. The low-pressure gas refrigerant that has flowed out ofthe indoor heat exchanger 121 flows into the outdoor unit 110 throughthe gas main pipe 101. The low-pressure gas refrigerant that has flowedinto the outdoor unit 110 passes through the switching valve 112 and theaccumulator 114, and is sucked into the compressor 111 again. The samecan be applied when the low-pressure refrigerant is supplied to thehot-water supply unit 130.

<Controller>

FIG. 1 shows that the system 10 includes an outdoor controller 100, twoindoor controllers 200 corresponding to each indoor unit 120 a, 120 b,respectively, and a hot-water supply controller 300. The outdoorcontroller 100, the indoor controllers 200 and hot-water supplycontroller 300 constitute a controller that is configured to control theentire operation of the system 10. The location of each controller 100,200, 300 and distribution of functions of each controller 100, 200, 300are not limited as long as they can communicate with each other and withmeasurement devices of the system 10. For example, all controllers canbe centralized into one controller and be disposed on the outdoor unit110. In another embodiment, functions of the outdoor controller 100 andeach indoor controller 200 are distributed therebetween differently fromthe present embodiment.

The outdoor controller 100, the indoor controllers 200 and hot-watersupply controller 300 transmit information to each other by wireless orwired communication means. In the present embodiment, the outdoorcontroller 100 informs the current operation at a predetermined intervalof time to the indoor controller 200 of each indoor unit 120 a, 120 bwhich is turned-on and the hot-water supply controller 300. An indoorcontroller 200 of a turned-on indoor unit 120 a, 120 b transmits itscurrent status to the outdoor controller 100 at a predetermined intervalof time. The hot-water supply controller 300 is configured to send arequest for hot-water supply to the outdoor controller 100.

<Outdoor Controller 100>

The outdoor controller 100 is configured to control the pressure and thetemperature of the refrigerant in the outdoor unit 110. The outdoorcontroller 100 is further configured to control the frequency of thecompressor 111, the switching valve 112, and the rotation speed of theoutdoor fan 115.

<Indoor Controller 200>

Each indoor unit 120 a, 120 b has an indoor controller 200. Hereinafter,the indoor unit controller 200 of the indoor unit 120 a is explained asan example. The same explanation is applicable to the indoor controller200 of any other indoor unit 120 b in the system 10.

The indoor controller 200 is configured to control the degree ofsuperheat of the indoor unit 120 a during the cooling operation, andcontrol the degree of subcooling of the indoor unit 120 a during theheating operation. The indoor controller 200 is configured to controlthe rotation speed of the indoor fan 123 a. The indoor controller 200 isconfigured to control the opening degree of the expansion valve 122 a.

<Hot-Water Supply Controller 300>

The hot-water supply controller 300 is configured to control the degreeof subcooling of the hot-water supply unit 130 during the heatingoperation. The hot-water supply controller 300 is configured to controlthe opening degree of the expansion valve 132. The hot-water supplycontroller is configured to control a valve, a pump, or the like.Although not shown in FIG. 1, components are arranged in the hot-watersupply unit 130 for controlling the water flow rate.

The hot-water supply controller 300 is configured to send a request forhot-water supply (hereinafter hot-water request) to the outdoorcontroller 100. The hot-water supply controller sends the hot-waterrequest in accordance with, for example, the temperature and/or theamount of the water stored in the water tank 133, and/or a time of aday.

Preferably, the hot-water supply controller 300 monitors the temperatureof the hot water stored in the hot water tank 133. When it determinesthat the current water temperature is below a target temperature set bya user or below a threshold temperature calculated from the targettemperature, the hot-water supply controller 300 sends the hot-waterrequest. Thereby, the hot water stored in the hot-water tank 133 isconstantly kept at the target temperature.

<Operation for Resuming a Cooling Operation After a Heating Operation>

In addition to the functions mentioned above, the controller 100, 200,300 determines if the hot-water request has occurred during a coolingoperation at at least one indoor unit 120 a. If yes, the controller 100,200, 300 start the heating operation, and determines the time point toresume the cooling operation based on at least one of an outdoortemperature and a target temperature of at least one indoor unit.Thereby, the duration period of the heating operation is limited in thisway, and the users' comfort can be ensured.

The functions of the outdoor controller 100 and the indoor controller200 are further explained in detail below.

<Outdoor Controller 100>

FIG. 2 is a block diagram showing functions of the outdoor controller100. The outdoor controller 100 has an operation unit 101, a receiver102, an update unit 103, a memory 104, a compressor unit 105, aThermo-off unit 106, a fan unit 107, and a valve unit 108.

The operation unit 101 controls the heating operation and coolingoperation mentioned above.

The operation unit 101 is further configured to monitor the hot-waterrequest from the hot-water supply controller 300. The operation unit 101is configured to determine if the hot-water request has occurred duringa cooling operation at at least one indoor unit 120 a. If yes, theoperation unit 101 is configured to stop the cooling operation, switchthe cooling circuit into the heating circuit, and start the heatingoperation.

The operation unit 101 is further configured to transmit to all of theindoor units 120 a, 120 b in the cooling operation a fan-stop signal tostop the indoor fan 123 a, 123 b arranged at each indoor unit.Accordingly, the operation unit 101 is configured to instruct the fanunit 107 to transmit a fan-stop command to all indoor units which areturned on for the cooling operation. The fan-stop command is a commandto stop an indoor fan arranged at an indoor unit. A command forcontrolling an indoor fan arranged at each indoor unit is created andtransmitted by the fan unit 107 in accordance with the instruction ofthe operation unit 101. Preferably, the fan-stop command is transmittedbefore the heating operation starts. More preferably, the fan-stopcommand is transmitted substantially at the same time when the coolingoperation stops. Thereby, no warm wind blows out of an indoor unit whichwas turned on for the cooling operation.

The operation unit 101 is further configured to determine the time pointto resume the cooling operation based on at least one of an outdoortemperature and a target temperature of at least one indoor unit in theheating operation. The operation unit 101 preferably resumes the coolingoperation when the biggest absolute value of a difference between theoutdoor temperature and any one of the target temperatures goes beyond apredetermined threshold value. As explained later, the outdoorcontroller 100 receives and stores in the memory 104 the targettemperatures of all indoor units 120 a, 120 b in operation. Thereby, thesystem can resume the cooling operation at an appropriate time pointbased on the outside temperature and/or a target temperature of anyindoor unit. The duration period of the heating operation is limited inthis way, and therefore the user's comfort can be ensured.

Preferably, the operation unit 101 continues the cooling operation afterthe hot-water request has occurred. The operation unit 101 is preferablyconfigured to determine if a predetermined condition is satisfied whilecontinuing the cooling operation after the hot-water request. Ifsatisfied, the operation unit 101 stops performing the cooling operationand starts a heating operation. The details of the condition to stop thecooling operation will be explained later. Accordingly, the coolingoperation at the indoor unit 120 a is not immediately interrupted by thehot-water request. The area where the indoor unit 120 a is performingthe cooling operation is further cooled down even after the hot-waterrequest. Therefore, users' comfort can be ensured in the area for awhile even after the cooling operation stops.

Preferably, the operation unit 101 is further configured to stop thecompressor 111 and an indoor fan of each indoor unit in the coolingoperation substantially at the same time. Accordingly, the operationunit 101 is preferably further configured to instruct the fan unit 107and the compressor unit 105 to transmit the fan-stop command and acompressor-stop command, respectively, substantially at the same time.The compressor-stop command is a command to stop a motor for driving thecompressor 111. A command for controlling the compressor 111 is createdand outputted by the compressor unit 105 in accordance with theinstruction of the operation unit 101.

Preferably, the operation unit 101 is further configured to maintain theindoor valves of all indoor units 120 a, 120 b in a predetermined opendegree during the heating operation. The operation unit 101 ispreferably configured to instruct the valve unit 108 to transmit a valvecommand to all indoor units 120 a, 120 b. The valve command is a commandto maintain each expansion valve 122 a, 122 b of each indoor unit at apredetermined open degree. The valve command is created and transmittedby the valve unit 108 in accordance with the instruction of theoperation unit 101.

A preferable example of the timing point for transmitting the fan-stopcommand, the compressor-stop command, and the valve command is shown inFIG. 6, which will be explained later.

The operation unit 101 is preferably further configured to increase thepower of the cooling operation which is performed after the hot-waterrequest has occurred and before the heating operation starts. Thedetails to increase the power of the cooling operation will be explainedlater.

The receiver 102 is configured to receive a “Request signal” from eachindoor unit 120 a, 120 b at a predetermined time interval. The receiver102 is further configured to receive the measurement information such asthe outside temperature detected by a sensor 310.

The “Request signal” includes an identification of an indoor unit andpreferably current status of the indoor unit. An example of the currentstatus is any one or combination of: ON/OFF, the operation for which theindoor unit is turned on, a target room temperature, a current roomtemperature, a wind level, and a “Request level”.

The “Request level” indicates a required change in the power of acooling operation. The “Request level” is expressed by, for example, anumeral value that corresponds to a predetermined step width toincrease/decrease the rotation frequency of the compressor 111. Theoperation unit 101 determines based on the “Request level” how much therotation frequency of the compressor 111 should be increased ordecreased.

The update unit 103 is configured to update data stored in the memory104 in accordance with the received data.

The memory 104 stores a status table and a level table. The contents ofeach table will be explained later.

The compressor unit 105 creates a command to control the rotationfrequency of the compressor 111 in accordance with the instruction fromthe operation unit 101, and outputs the created command to the driver ofthe motor of the compressor 111.

The Thermo-off unit 106 creates a command to change a “Thermo-off”temperature at an indoor unit, and transmits the command to one or morerelevant indoor units in accordance with the instruction from theoperation unit 101.

When a current room temperature in an area of a corresponding indoorunit has reached to its “Thermo-off” temperature, the indoor unit turnsinto a “Thermo-off” status. This means that the indoor unit stopsperforming the cooling operation by completely closing the correspondingexpansion valve. A “Thermo-off” temperature of an indoor unit is lowerthan a target temperature of the indoor unit for a cooling operation. A“Thermo-off” temperature of an indoor unit is higher than a targettemperature of the indoor unit for a heating operation. The differencebetween the “Thermo-off” and target temperatures is, for example, 1 to 3degree. It is preferable that the difference between the “Thermo-off”and target temperature is larger for the cooling operation after theoccurrence of the hot-water request than for a normal cooling operation.The detail will be explained later in “Increase of the power of thecooling operation.”

The fan unit 107 creates a command to change the rotation frequency ofan indoor fan, and transmits the command to one or more relevant indoorunits in accordance with the instruction from the operation unit 101.

The valve unit 108 creates a command to change an open degree of anexpansion valve of an indoor unit, and transmits the command to one ormore relevant indoor units in accordance with the instruction from theoperation unit 101.

<Level Table in the Memory 104 of the Outdoor Controller 100>

FIG. 3 shows a level table stored in the memory 104 of the outdoorcontroller 100. The level table associates a numeral value correspondingto each request level with a step width to increase or decrease therotation frequency of the compressor 111. Each value of the step widthcorresponds to a predetermined change in the rotation frequency of thecompressor 111.

The “Request level 0” indicates that a room temperature has reached tothe Thermo-off temperature of a corresponding area. In other words, the“Request level 0” indicates that the indoor unit in the correspondingarea has turned into the “Thermo-off” status. Such an indoor unitrequests no change in the rotation frequency of the compressor 111. The“Request level 1, 2, and 3” indicate that the power of the currentoperation should be lowered. The “Request level 4, 5, and 6” indicatethat the power of the current operation should be increased.

The operation unit 101 is preferably configured to choose one “Requestlevel” which has the biggest absolute value to change the rotationfrequency of the compressor 111.

<Status Table in the Memory 104>

FIG. 4A shows an example of a status table stored in the memory 104 ofthe outdoor controller 100. The status table stores “area,” “Requestlevel,” “operation status,” “target temperature,” “wind level,” and“current temperature” in associated with each other.

The “Request level” is as explained above. The “area” corresponds to anarea and identifies an indoor unit installed in the area. The operationstatus indicates if the indoor unit is turned on or off, and theoperation for which the indoor unit is turned on. The target temperatureindicates a temperature to which a room temperature of the area of thecorresponding indoor unit should be reached. The wind level indicatesthe level of the rotation frequency of the indoor fan. The currenttemperature indicates a current temperature of the area of the indoorunit.

The “Request level 0” means that the indoor unit has turned into the“Thermo-off” status. In FIG. 4A, the indoor unit in the “area 1” isturned on for a cooling operation, and has already turned into the“Thermo-off” status. On the other hand, the indoor units in the “area 2”and “area 3” are turned on for the cooling operation, but have notturned into the “Thermo-off” status yet since each “Request level” ismore than zero.

<Predetermined Condition to Stop the Cooling Operation>

Preferably, the operation unit 101 is configured to continue the coolingoperation after receiving the hot-water request. The operation unit 101continues the cooling operation until receipt of a “Request signal”having the “Request level 0” from each of all indoor units in thecooling operation, and starts the heating operation. The “Requestsignal” having the “Request level 0” indicates that the indoor unit hasturned into the “Thermo-off” status. The operation unit 101 stops thecooling operation after receiving the “Request signal” having “Requestlevel 0” from all indoor units which are turned on for the coolingoperation. Thereby, user's comfort for the cooling operation can befurthermore ensured.

The operation unit 101 is preferably configured to continue the coolingoperation until a predetermined period of time P1 has passed since thehot-water request. After the time period P1 has passed since thehot-water request, the operation unit 101 is configured to stop thecooling operation.

The operation unit 101 preferably adopts any one of or combination ofthe above mentioned conditions to stop the cooling operation.

<Increase of the Power of the Cooling Operation>

The operation unit 101 is preferably configured to increase the power ofthe cooling operation before starting the heating operation. Preferableexamples for increasing the power are explained below.

EXAMPLE 1

The operation unit 101 is preferably configured to perform, after thehot-water request has occurred and before the heating operation starts,the cooling operation at all indoor units which are already turned onfor the cooling operation at the time point of the occurrence of thehot-water request.

In this application, an “indoor unit which is turned on for the coolingoperation” is either one of an indoor unit that has turned into the“Thermo-off” status and an indoor unit that is performing the coolingoperation. An “indoor unit in the cooling operation” means the same asan “indoor unit which is turned on for the cooling operation.”

Even if all indoor units in the cooling operation have already turnedinto the “Thermo-off” status when the hot-water request occurred, theindoor units are preferably forced to perform the cooling operation.Thereby, the cooling operation is forced to be performed in theThermo-off status area, and the power of the cooling operationincreases. If one of the indoor units in the cooling operation is stillperforming the cooling operation while the others have turned into the“Thermo-off” status as the hot-water request occurred, the latter indoorunits are forced to perform the cooling operation.

EXAMPLE 2

The operation unit 101 is preferably configured to perform the coolingoperation at all of the indoor units 120 a, 120 b after the hot-waterrequest has occurred and before the heating operation starts.

Even if only the indoor unit 120 a is turned on for the coolingoperation and the indoor unit 120 b is turned off, not only the indoorunit 120 a but also the indoor unit 120 b are forced to perform thecooling operation. As mentioned above, if the indoor unit 120 a isturned on and already has turned into the “Thermo-off” status, it isalso forced to perform the cooling operation. Thereby, all indoor unitsin the system 10 are forced to perform the cooling operation, and thepower of the cooling operation increases. The indoor unit 120 b, whichwas previously turned off at the time of the hot-water request, isforced to perform a cooling operation in the corresponding area.Accordingly, the user comfort can be ensured in any area even after thecooling operation has already stopped and the heating operation hasbegun.

EXAMPLE 3

The operation unit 101 is preferably configured to instruct thecompressor unit 105 to output, during the cooling operation and afterthe hot-water request has occurred, a command to increase the rotationfrequency thereof. The operation unit 101 preferably stores apredetermined value to increase amount of the rotation frequency. Thecompressor unit 105 creates a command based on the instruction of theoperation unit 101 and outputs the command to the driver of the motor ofthe compressor 111.

EXAMPLE 4

The operation unit 101 is preferably configured to instruct theThermo-off unit 106 to transmit, during the cooling operation and afterthe request has occurred, a command to lower a Thermo-off temperature ofeach indoor unit performing the cooling operation. The instructionpreferably specifies the change amount in the Thermo-off temperaturebased on each target temperature of the corresponding indoor unit.Alternatively, the operation unit 101 preferably lowers the Thermo-offtemperature by a predetermined value. Such a predetermined value ispreferably larger than another predetermined value to set the Thermo-offtemperature during a normal cooling operation other than an operationfor increasing the power of the cooling operation upon the hot-waterrequest. For example, the operation unit 101 sets the Thermo-offtemperature at a temperature two-degree lower than the targettemperature when increasing the power of the cooling operation upon thehot-water request. Otherwise, the Thermo-off temperature is set at atemperature one-degree lower than the target temperature. The Thermo-offunit 106 preferably transmits the command to all indoor units which areperforming the cooling operation.

EXAMPLE 5

The operation unit 101 is preferably configured to instruct the fan unit107 to transmit, during the cooling operation and after the request hasoccurred, a command to indicate an increase amount of a rotationfrequency of each indoor unit performing the cooling operation. Theinstruction preferably specifies the increase amount of the rotationfrequency based on, for example, the outside temperature, apre-determined value of increase amount, a difference between a currentroom temperature and a target temperature. The fan unit 107 creates thecommand in accordance with the instruction and transmits the command toall indoor units which are performing the cooling operation.

EXAMPLE 6

The operation unit 101 is preferably configured to instruct the valveunit 108 to transmit to all indoor units 120 a in the cooling operation,during the cooling operation and after the request has occurred, acommand to decrease an open degree of each expansion valve 122 a. Theinstruction preferably identifies the open degree of each expansionvalve or a change amount in the open degree. The valve unit 108 createsthe command in accordance with the instruction and transmits the commandto all indoor units which are performing the cooling operation.

EXAMPLE 7

The operation unit 101 is preferably configured to instruct thecompressor unit 105 to create and output a command to the compressor 111during the cooling operation and after the request has occurred. Theinstruction specifies the increase amount of the rotation frequency ofthe compressor 111 by a predetermined value which is independent fromeach “Request level” stored in the status table in the memory 104. Inother words, even in the case none of the indoor units that is turned onfor the cooling operation transmits a “Request level” to increase thepower of the cooling operation, the rotation frequency of the compressor111 increases. Thereby, the power of the cooling operation is forced toincrease.

The operation unit 101 may perform any one or any combination of theabove-mentioned examples to increase the power of the cooling operation.

<Indoor Controller 200>

FIG. 5 is a block diagram showing functions of the indoor controller 200of the indoor unit 120 a. The explanation below is applicable to otherindoor units. The indoor controller 200 has an operation unit 201, areceiver 202, an update unit 203, a memory 204, a request unit 205, afan unit 206, and a valve unit 207.

The operation unit 201 controls the heating operation and coolingoperation mentioned above.

The receiver 202 receives commands from the outdoor controller 100. Thereceiver 202 receives inputs from the input device (not shown) tocontrol the indoor unit 120 a. The receiver 202 receives a current roomtemperature detected by a sensor 320.

The update unit 203 updates a status table stored in the memory 204based on the data received by the receiver 202. FIG. 5B shows the statustable stored in the memory 204 of the indoor controller 200. The statustable stores the Thermo-off temperature in addition to the data storedin the status table in the memory 104 of the outdoor controller 100. Theexplanation of the data stored in the outdoor controller 100 isapplicable to the common data stored in the indoor controller 200.

The request unit 205 creates the “Request signal” based on the datastored in the status table. The request unit 205 transmits the “Requestsignal” to the outdoor controller 100 at the predetermined timeinterval. The “Request signal” includes, as explained above, anidentification of an indoor unit and preferably current status of theindoor unit.

The fan unit 206 outputs a signal to a driver of the motor of thecorresponding indoor fan 123 a to stop the motor in accordance with thefan-stop command from the outdoor controller 100. The fan unit 206outputs a signal to the driver of the motor of the corresponding indoorfan 123 a to change the rotation frequency of the motor in accordancewith an input from the input device.

The valve unit 207 controls the open degree of the expansion valve 122 ain accordance with the instruction from the operation unit 201. Further,the valve unit 207 outputs a signal to the corresponding expansion valve122 a to change the open degree of the expansion valve 122 a inaccordance with the data received by the receiver 202. The received datais, for example, the command sent from the outdoor controller 200 todesignate a specific open degree.

FIG. 10 shows one of the examples of the locations where the sensor 320is arranged. In this example, the sensor 320 is arranged directly on thehousing of the indoor unit. Such a sensor 320 arranged within or on thehousing of the indoor unit cannot precisely detect a current roomtemperature during the heating operation in a case the correspondingindoor fan is stopped by the fan-stop command. Accordingly, it isadvantageous to decide the resume timing based on the outsidetemperature and any one of the target temperatures without using anycurrent room temperature.

<Time Chart>

FIG. 6 shows a preferable example of a time chart for switching from acooling operation to a heating operation triggered by the hot-waterrequest. The operation mode is switched from the cooling operation intothe heating operation by the hot-water request occurred at a time t0during the cooling operation.

The compressor unit 105 of the outdoor controller 100 outputs thecompressor-stop command to stop the compressor 111 at a time t1, whichis preferably after a while from the time t0. Thereby, the compressor111 stops working and the cooling operation ends. The compressor unit105 further outputs a second command (hereinafter a compressor-startcommand) to drive the compressor 111 at a time t2 which is after a shorttime period Pw from the time t1.

The operation unit 101 of the outdoor controller 100 outputs a switchcommand to switch the switching valve 112 from the cooling operationposition to the heating operation position. The switching valve 112 isswitched after the time t1 when the compressor 111 stops for the coolingoperation and before or at the latest the time t2 when the compressor111 starts operation again. The switch command is preferably outputtedsubstantially simultaneously at the time t2 when the compressor 111starts operation again. Thereby, the refrigerant circuit is switchedinto the heating circuit at the end of the time period Pw.

The fan unit 107 of the outdoor controller 100 transmits the fan-stopcommand to stop an indoor fan. The fan-stop command is transmitted atthe time t1 at the earliest and no later than the time t2 when thecompressor 111 starts operation again. Preferably, the fan-stop commandis transmitted substantially simultaneously at the time t1 when thecompressor-stop command is outputted. The fan-stop command istransmitted to all indoor units performing the cooling operation. Thefan unit 206 of each indoor unit outputs a signal to stop thecorresponding indoor fan accordingly.

Thereby, no warm wind blows out during the heating operation in an areawhere an indoor unit is turned on for the cooling operation.

<Flow of Process>

<Main Process of the Outdoor Controller 100>

FIGS. 7A and 7B show an example of the main process performed by theoutdoor controller 100. The main process starts when the outdoor unit isturned on.

The outdoor controller 100 monitors if the hot-water supply controllerrequests for the hot-water supply (step S1). If yes, the processproceeds to step S2.

The outdoor controller 100 determines if the current operation is acooling operation (step S2). If yes, the process proceeds to step S3. Ifnot, the process proceeds to step S8 which will be explained later.

The outdoor controller 100 determines if all indoor units in the coolingoperation have turned into the “Thermo-off” status (step S3). Thereby,it can be ensured that the heating operation starts only after a currentroom temperature of each area in the cooling operation has reached to atarget temperature. If yes, the process proceeds to step S6 mentionedlater. If no, the process proceeds to step S4.

The outdoor controller 100 performs an increase process at the step S4.The increase process increases the power of the cooling operation whichis currently being performed. Thereby, each area in the coolingoperation can be quickly cooled down before the heating operationstarts.

The outdoor controller 100 repeats the increase process at the step S4until all indoor units in the cooling operation turn into the“Thermo-off” status (step S3), or until the predetermined time period P1passes from the occurrence of the hot-water request (step S5). The stepS5 can ensure the minimum period of time P1 to keep the coolingoperation in active even after the hot-water request. If yes at eitherone of the steps S3 and S5, the process proceeds to step S6.

The outdoor controller 100 outputs the compressor-stop command and stopsthe rotation of the compressor 111 (step S6). Thereby, the coolingoperation ends. In addition, the outdoor controller 100 transmits thefan-stop command to stop an indoor fun to all indoor units which wereturned on for the cooling operation (step S6). Thereby, during thesubsequent heating operation, no warm wind blows out of the indoor unitswhich were turned on for the cooling operation.

The outdoor controller 100 determines if a predetermined time period Pwhas passed after the output of the compressor-stop command (step S7).After the time period Pw has passed, the process proceeds to step S8.

The outdoor controller 100 transmits the valve command to all indoorunits to keep the corresponding expansion valves slightly open (stepS8). Thereby, a small amount of the refrigerant flows through eachindoor unit during the heating operation which will be subsequentlyperformed. Accordingly, the entire amount of the refrigerant circulatesin the refrigerant circuit during the heating operation withoutstagnation.

After the time period Pw has passed from the compressor-stop command,the outdoor controller 100 switches the switching valve 112 into theheating operation position, and starts driving the motor of thecompressor 111 (step S9). Thereby, the heating operation starts. Thehot-water supply is performed during the heating operation, and thewater stored in the water tank 133 is heated up.

The outdoor controller 100 determines if an absolute vale of adifference between any target temperature and the outside temperature ismore than a predetermined threshold value (step S10). When the absolutevale of the difference goes beyond the threshold value in any area whichwas in the cooling operation prior to the heating operation, it is thetime to resume a cooling operation. If yes, the process proceeds to stepS11.

The outdoor controller 100 stops the rotation of the motor of thecompressor 111 (step S11). Thereby, the heating operation and thehot-water supply end.

The outdoor controller 100 switches the switching valve 112 into thecooling operation position, and drives the motor of the compressor 111to resume a cooling operation (step S12).

The outdoor controller 100 repeats the steps S1 to S12 mentioned aboveuntil the outdoor unit is turned off (step S13).

The flow of the process above is an example and is not limited thereto.For example, in another embodiment, the condition to stop the coolingoperation may be either one of or the combination of the steps S3 andS5.

In another embodiment, the increase process at step S4 may be omitted.

As for the condition to quit the heating operation, as an alternative ofa step 10, a difference between any current room temperature and acorresponding target temperature may be used.

<Increase Process of the Outdoor Controller 100>

FIG. 8 shows an example of the flow of increase process performed duringthe main process in FIG. 7A, 7B by the outdoor controller 100. At stepS4 of the main process, the outdoor controller 100 performs the increaseprocess to increase the power of the cooling operation which iscurrently being performed after the hot-water request.

The outdoor controller 100 transmits a command to lower each Thermo-offtemperature at each indoor unit which is performing the coolingoperation (step S41).

The outdoor controller 100 transmits a command to increase the rotationfrequency of the indoor fan of each indoor unit which is performing thecooling operation (step S42). Thereby, the amount of wind from eachindoor unit increases.

The outdoor controller 100 transmits a command to slightly close theexpansion valve of each indoor unit which is performing the coolingoperation (step S43). Thereby, an evaporation temperature of each indoorunit is lowered, which increases the power of the cooling operation.

The outdoor controller 100 determines if any increase of the coolingoperation is requested by any one of the indoor units which areperforming the cooling operation (step S44). The determination is madebased on the “Request level” of each indoor unit stored in the statustable in the memory 104. If yes, the process proceeds to the step S45.If no, the process proceeds to step S46.

The outdoor controller 100 increases the rotation frequency of thecompressor 111 in accordance with the highest request level in thestatus table in the memory 104 (step S45).

The outdoor controller 100 increases the rotation frequency of thecompressor 111 based on the predetermined step width of increase (stepS46). Thereby, the power of the cooling operation increases even whennone of indoor units in the cooling operation requests an increase ofpower of the cooling operation.

The order of the steps S41 to S46 is not limited to the one mentionedabove. Any one or more steps among the steps S41 to S46 may be omitted.

<Main Process of Indoor Controller 200>

FIG. 9 shows an example of the main process performed by the indoorcontroller 200. The indoor main process starts when an indoor unit isturned on.

The indoor controller 200 monitors the current operation transmittedfrom the outdoor controller 100 at a predetermined time interval (stepS201). The process proceeds to step S202 upon the receipt of the currentoperation mode.

The indoor controller 200 determines if the current operation willchange from a cooling operation into a heating operation (step S202). Ifyes, the process proceeds to step S203. If no, the process returns tostep S201.

The indoor controller 200 increases the power of the cooling operationcurrently running in accordance with a command from the outdoorcontroller 100 (step S203). For example, the indoor controller 200changes based on the command a rotation frequency of the correspondingindoor fan, the Thermo-off temperature, and/or the open degree of thecorresponding expansion valve.

The indoor controller 200 receives the fan-stop command from the outdoorcontroller 100 to stop a corresponding indoor fan. The indoor controller200 stops the corresponding indoor fan in accordance with the fan-stopcommand (step S204). Thereby, no warm window blows out of the indoorunit during the heating operation which will be subsequently performed.

The indoor controller 200 receives the valve command from the outdoorcontroller 100, and controls the open degree of the correspondingexpansion valve in accordance with the valve command (step S205).Thereby, it can be ensured that the entire amount of the refrigerant cancirculate within the refrigerant circuit during the heating operation.

The indoor controller 200 repeats the step 201 to 205 mentioned aboveuntil the indoor unit is turned off (step S206).

In the main process of the indoor controller 200 mentioned above, thestep 203 may be omitted in the case the main process of the outdoorcontroller 100 does not perform the increase process.

Modifications

Followings are other preferred embodiments according to the system ofthe present invention.

First Modification

FIG. 10 shows a system 10′ according to a modification of the system 10in the above embodiment. The system 10′ is different from the system 10in that each expansion valve corresponding to each indoor unit or ahot-water supply unit is arranged in an outdoor unit. In FIGS. 1 and 10,the components with the same reference signs in the systems 10, 10′ havethe same or corresponding function. Accordingly, only the differencebetween the systems 10, 10′ will be explained below. The commoncomponents and/or functions between the systems 10, 10′ can be referredto in the explanation about the system 10 above.

The system 10′ in FIG. 10 has an outdoor unit 110′, at least one indoorunits 120 a′, 120 b′, and a hot-water supply unit 130′, which areconnected to each other. Each unit in the system 10′ is connected witheach other in the same manner as the connection in the system 10.

The outdoor unit 110′ has expansion valves 122 a, 122 b, 132 which arearranged for each of the indoor units 120 a′, 120 b′ and the hot-watersupply unit 130′, respectively. The structure of each expansion valve122 a, 122 b, 132 is the same as expansion valve in the system 10. Theconnections between each expansion valve 122 a, 122 b, 132 and othercomponents in the system 10′ are the same as expansion valve in thesystem 10.

The outdoor unit 110′ has an outdoor controller 100′. The outdoorcontroller 100′ has the same function as the outdoor controller 100 inthe system 10, and further has the function to control the openingdegree of each of the expansion valves 122 a, 122 b, 132.

Each indoor unit 120 a′, 120 b′ has an indoor controller 200′. Theindoor controller 200′ has the same function as the indoor controller200 in the system 10 other than the function for controlling acorresponding expansion valve.

The hot-water supply unit 130 has a hot-water supply controller 300′.The hot-water supply controller 300′ has same function as the hot-watersupply controller 300 in the system 10 other than the function forcontrolling a corresponding expansion valve.

Second Modification

The functions of the outdoor controller 100, 100′, each indoorcontroller 200, 200′, and the hot-water supply controller 300 may bedistributed therebetween differently from the systems 10, 10′ mentionedabove. For example, a part of controls performed by the indoorcontroller 200, 200′ may be alternatively performed by the correspondingoutdoor controller 100, 100′, and vice versa. The control of anycomponent in the systems 10, 10′ may be switched between the outdoorcontroller 100, 100′ and indoor controller 200, 200′ in accordance witha predetermined condition.

For example, the outdoor controller 100, 100′ may generate a command tocontrol the expansion valves 122 a, 122 b, 132, and transmit the commanddirectly to the expansion valves 122 a, 122 b, 132. Likewise, theoutdoor controller 100, 100′ may generate a command to control theindoor fans 123 a, 123 b, and transmit the command directly to theindoor fans 123 a, 123 b. It is preferable to control the expansionvalves 122 a, 122 b, 132 and the indoor fans 123 a, 123 b by the outdoorcontroller 100, 100′ after the hot-water request during the coolingoperation and until the end of the subsequent heating operation.

It is further preferable that the expansion valves 122 a, 122 b, 132 andthe indoor fans 123 a, 123 b are independently controlled by thecorresponding indoor controller 200 or the hot-water supply controller300 during a normal operation period. A normal operation period is otherthan the period “after the hot-water request during a cooling operationand until the end of the heating operation subsequently performed afterthe cooing operation.”

While only selected embodiments have been chosen to illustrate thepresent invention, it will be apparent to those skilled in the art fromthis disclosure that various changes and modifications can be madeherein without departing from the scope of the invention as defined inthe appended claims. For example, unless specifically stated otherwise,the size, shape, location or orientation of the various components canbe changed as needed and/or desired so long as the changes do notsubstantially affect their intended function. Unless specifically statedotherwise, components that are shown directly connected or contactingeach other can have intermediate structures disposed between them solong as the changes do not substantially affect their intended function.The functions of one element can be performed by two, and vice versaunless specifically stated otherwise. The structures and functions ofone embodiment can be adopted in another embodiment. It is not necessaryfor all advantages to be present in a particular embodiment at the sametime. Thus, the foregoing descriptions of the embodiments according tothe present invention are provided for illustration only.

The invention claimed is:
 1. A system for air-conditioning and hot-watersupply and configured to alternatively perform an air cooling operationand a water heating operation, comprising: an outdoor unit having acompressor and an outdoor heat exchanger; at least one or more indoorunits each of which is connected to the outdoor unit and includes anindoor heat exchanger; a hot-water supply unit connected to the outdoorunit so as to be arranged in parallel to the at least one or more indoorunits and including a refrigerant-water heat exchanger; and a controllerconfigured to monitor an occurrence of a request for hot-water supplyfrom the hot-water supply unit during the cooling operation performed atat least one of the indoor units, and then to start the water heatingoperation; wherein the controller is further configured to determine atime to resume said cooling operation based on an outdoor temperatureand/or a target temperature of at least one indoor unit in said heatingoperation, wherein the controller is further configured to determine thetime to resume said cooling operation so that a period of the waterheating operation becomes shorter as the outdoor temperature is higherand/or as the target temperature of at least one indoor unit is lower.2. The system for air-conditioning and hot-water supply according toclaim 1, wherein the controller is further configured to perform saidcooling operation until receipt of a signal from each of all indoorunits in said cooling operation, and then to start said heatingoperation; and the signal indicating that a current room temperature hasreached a target temperature of a corresponding indoor unit.
 3. Thesystem for air-conditioning and hot-water supply according to claim 1,wherein the controller is further configured to determine the time toresume said cooling operation based on a difference between the outdoortemperature and any one of target temperatures of one or more indoorunits which were in said cooling operation.
 4. The system forair-conditioning and hot-water supply according to claim 1, wherein atleast one of the indoor units includes a sensor within or on itshousing, the sensor being configured to detect a room temperature. 5.The system for air-conditioning and hot-water supply according to claim2, wherein the controller is further configured to determine the time toresume said cooling operation based on a difference between the outdoortemperature and any one of target temperatures of one or more indoorunits which were in said cooling operation.
 6. The system forair-conditioning and hot-water supply according to claim 2, wherein atleast one of the indoor units includes a sensor within or on itshousing, the sensor being configured to detect a room temperature. 7.The system for air-conditioning and hot-water supply according to claim3, wherein at least one of the indoor units includes a sensor within oron its housing, the sensor being configured to detect a roomtemperature.